# Running Workflows via API

Workflows can be triggered from the API by calling `run_workflow`. This method is available on the `hatchet.client.admin` client:

```python filename="run_workflow.py" copy
from hatchet_sdk import Hatchet, ClientConfig

hatchet = Hatchet()

workflowRun = hatchet.client.admin.run_workflow(
    "ManualTriggerWorkflow",
    {"test": "test"},
    options={"additional_metadata": {"hello": "moon"}},
)
```

This method takes the following parameters:

- `workflow_name` (**required**): The name of the workflow to trigger. If you have not overridden the workflow name in the `hatchet.workflow` decorator, this should match the name of the workflow class.
- `input` (**required**): The input to the workflow. This should be a JSON-serializable dict.
- `options` (**optional**): Additional options to pass to the workflow. The current options are supported:
  - `additional_metadata`: A dict of key-value strings to attach to the workflow run. This metadata will be shown in the Hatchet UI and will be available in API endpoints for listing/filtering.

For more information on how to interact with the return value of `run_workflow`, see the documentation for [getting workflow run results](./get-workflow-results).

### Running Workflows in Bulk via API

Workflows can also be triggered in bulk by calling `run_workflows`. This method is available on the `hatchet.client.admin` client:

```python filename="run_workflows.py" copy
from hatchet_sdk import Hatchet, ClientConfig

hatchet = Hatchet()

workflowRuns: WorkflowRun = []

for i in range(20):
    workflowRuns.append(
        {
            "workflow_name": "BulkParent",
            "input": {"n": i},
            "options": {
                "additional_metadata": {
                    "bulk-trigger": i,
                    "hello-{i}": "earth-{i}",
                },
            },
        }
    )

workflowRunRefs = hatchet.admin.run_workflows(
    workflowRuns,
)

```

This method takes the following parameters:

- `workflow_runs` (**required**): A list of WorkflowRun objects.
